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Project Design. Alain Esteva-Ramirez School of Computing and Information Sciences Florida International University. Bárbara Morales-Quiñones Department of Computer Engineering University of Puerto Rico-Mayaguez. REU Summer Program. 07/17/2007. Outline. Recap of Previous Phase
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Project Design Alain Esteva-Ramirez School of Computing and Information Sciences Florida International University Bárbara Morales-Quiñones Department of Computer Engineering University of Puerto Rico-Mayaguez REU Summer Program 07/17/2007
Outline • Recap of Previous Phase • Introduction • What are we doing now? • How the system will work • Request Scheduling • Diagrams • Algorithm outline • Goals • Questions?
Recap Where we left off last time… • Safe Adaptation with Validation Strategy to Testing AC Systems at Runtime • Performed background on safe adaptation (Zhang) • Focused on how to test self-optimization changes • Surveyed tools to support testing adaptive AC systems • Tools Survey • Looked at <number> of automated tools • Dependency Analysis: JDepend and Cap • Performance Metrics: TPTP • Unit Testing Support: Cobertura and JUnitPerf
Introduction What are we doing now? • Problem • Design an adaptable autonomic container. • Incorporate self-optimization capability • Apply container in the context of a real problem • Integrate tools to support validation of self-optimization • Solution • Autonomic Request Scheduling Container
How the system will work Autonomic Request Scheduling • Recall Stevens and Parsons autonomic stack of random numbers (REU 2006) • Stack self-configured by increasing size • Container will now hold user requests that need to be serviced. • Agents dequeue requests according to some high-level scheduling algorithm, and service them. • Self-optimization changes strategy in attempt to prevent starvation
How the system will work Request Scheduling Strategies • First come, first serve (FCFS) • Decision mode: non-preemptive • Comments: A potential problem is when a short request follows a long one. • Shortest Request Next (SRN) • Decision mode: non-preemptive • Comments: SRN is better than FCFS for short request, but long request may have to wait for some time for service. To avoid this problem, a request's time limit can be used.
Design Constraints • Need a flexible design to facilitate seamless integration of new components • E.g. New scheduling strategies • High-level design of autonomic system must conform with standard architecture of autonomic computing (IBM ‘06] • Self-testing framework must conform with safe adaptation with validation strategy (King et al.) • Reuse as much as possible, Patterns
Selected Design Patterns • Façade (Interface pattern) • Provides an interface that makes a subsystem easy to use • Strategy (Operation pattern) • Encapsulates alternate strategies in separate classes • Observer (Responsibility pattern) • Define a dependency between objects • When one changes state, dependents are notified and updated automatically
Algorithm Outline Strategy swap : FCFS to SRN • Precondition: Three agents and approximately 15 requests • FCFS is the current strategy. • Agent3 is at finished, the others are working on heavy requests. • Steps: • The Monitor of the TAMSelfOptim through RATouchData knows that the AgentPool has the third agent free. (1) • The Monitor of the TAMSelfConfig through RCTouchData knows that the next request in the RequestContainer is heavy.(2) • Both managers store that information in the Knowledge Source through the KSFacade. • The OAMReqSched analyses that information (1 and 2), thus changes the strategy in the SchedStratey to SRN. • Then the OAMReqShed notifies the TAMSelfOptim through the KSFacade that the third agent should be set to ready.
Activity Diagram • TAMSelfOptim detects that the Agent Pool has a free agent. • TAMSelfConfig detects that the next request in the Request Container is heavy. • Both managers write this state information to the Knowledge Source (KS). • OAMReqSched analyzes information from KS and detects that more than 60% of other agents are working on heavy requests. • OAMReqSched requests to swap strategy to SRN. • OAMReqSched notifies that a free agent is now ready.
Activity Diagram Strategy swap : FCFS to SRN
Goals • Have a solid adaptive framework • Test it during safe ad • Write a technical paper • Write a student paper
Questions? Questions, comments and queries.